Vertical bag form-fill-seal packaging machine

ABSTRACT

The present invention provides a first transfer unit instead of a stationary chute. The first drive unit drives the first transfer unit and is controlled to maintain a bag ejection interval or bag posture. Thus, variation of the bag-to-bag pitch and bag posture even in a high-speed operation with an improved bag-forming capacity is prevented.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a vertical bag form-fill-sealpackaging machine, and more particularly to a vertical bagform-fill-seal packaging machine for forming bags by sealing acontinuous tubular packaging material in which a product to be packagedis filled, and then separating and ejecting each of the bags.

[0003] 2. Background Information

[0004] Vertical bag form-fill-seal packaging machines exist as packagingdevices that fill a product to be packaged, such as food, into bagswhich are being formed at the same time. In a conventional vertical bagform-fill-seal packaging machine, a packaging material in a sheet-likefilm form is fed over a former and into a tube. The material is formedinto a tubular shape that conforms to the vertically long tube throughwhich it goes. The overlapped vertical ends of the tubular packagingmaterial are then sealed (heat-sealed) by a vertical sealing mechanism.The product to be packaged, which is allowed to drop from a higherposition, is filled into the tubular packaging material via the tube.Then, the portion of the tubular packaging material that will become thetop of a bag and the bottom of its next bag is transversely sealed by atransverse sealing mechanism provided under the tube. Immediately afterthis, a cutter cuts the center of the transversely sealed portion. Insuch a vertical bag form-fill-seal packaging machine, two types ofoperations, the forming of the bags and the filling of the product to bepackaged into the bags, are carried out continuously as described above.

[0005] In such a conventional vertical bag form-fill-seal packagingmachine, each of the bags separated from the following bag by the cutterfalls freely onto a stationary chute provided below the transversesealing mechanism, and is led to a belt conveyor in a downstreamprocess. The stationary chute is similar to a playground slide made of ametal plate or the like, and plays the role of transferring the bag tothe belt conveyor in the downstream process by taking advantage ofgravity.

[0006] In a conventional vertical bag form-fill-seal packaging machine,the bags are allowed to fall freely using gravity before they areejected onto the belt conveyer in the downstream process. Withimprovements in bag-forming capacity in recent years, however, thequantity of the bags ejected per unit of time has increased. With thetraditional quantities of bags to be ejected, a small degree ofvariation in the bag ejection interval and posture would not lead to aproblem on the belt conveyor or other devices in the downstream process.However, with the quantity of the bags to be ejected ever increasing, aproblem with the devices could result in the downstream process.Particularly, with the increase in the quantity of the bags to beejected, or the higher-speed operation of the vertical bagform-fill-seal packaging machine, which causes the bags to be ejected ata shorter interval, a minor variation in the bag ejection intervals maylead to a problem with the devices in the downstream process. Forexample, two bags may be loaded instead of one on a weight checker or aseal checker in the downstream process, or the mishandling of the bagsor the disorganization of the file or files of the bags may result at aboxing device. Such problems could stop the production line, thuslowering the line operation rate and preventing the achievement ofhigh-speed operation.

[0007] In view of the above, there exists a need for a vertical bagform-fill-seal packaging machine which overcomes the above mentionedproblems in the prior art. This invention addresses this need in theprior art as well as other needs, which will become apparent to thoseskilled in the art from this disclosure.

SUMMARY OF THE INVENTION

[0008] A principal object of the present invention is to provide avertical bag form-fill-seal packaging machine that prevents variation inthe pitch and posture of the bags that are continuously ejected.

[0009] A vertical bag form-fill-seal packaging machine in accordancewith a first aspect of the present invention provides a vertical bagform-fill-seal packaging machine for forming bags by sealing acontinuous tubular packaging material in which a product to be packagedis filled, and then separating and ejecting each of the bags. Thevertical bag form-fill-seal packaging machine includes a first transferunit, a first drive unit, and a control unit. The first transfer unittransfers the separated bags to another transfer unit or conveyorprovided in a downstream process. The first drive unit drives the firsttransfer unit. The control unit controls the first drive unit to controlthe interval or the posture of the bags to be ejected after beingtransferred by the first transfer unit. In this case, the first transferunit is provided instead of a conventional stationary chute. The baginterval and the posture of the bags to be ejected are maintained bycontrolling the first drive unit that drives the first transfer unit.Therefore, even during high-speed operation with an improved bag-formingcapacity, the variation in the pitch and the posture of the bags can bereduced. With a conventional stationary chute, on which frictionalresistance (as the bag slides) and an impact (as the bag comes off thechute) occurs, there is a high probability that the pitch and theposture of the bags may be adversely affected. By using the packagingmachine as defined in the first aspect of the present invention, inwhich the first transfer unit is provided and the transfer of the bag onthe first transfer unit is controlled, variations in the bag ejectionpitch and posture are prevented.

[0010] A vertical bag form-fill-seal packaging machine in accordancewith a second aspect of the present invention is the machine as definedin the first aspect, wherein the control unit provides control so thatthe bag ejection interval is larger than the bag separation interval.The bags are prevented from being transferred to the conveyor or thetransfer unit or other devices in the downstream process without aproper interval.

[0011] A vertical bag form-fill-seal packaging machine in accordancewith a third aspect of the present invention is the machine as definedin either of the previous aspects, wherein the first transfer unit is abelt.

[0012] In this aspect, a relatively simple structure having a belt and afirst drive unit for moving the belt, such as a motor, is used torestrict variation in the bag ejection pitch and posture. It is easy andinexpensive to incorporate this structure into a vertical bagform-fill-seal packaging machine of the present invention or duringinitial construction to retrofit it to a conventional vertical bagform-fill-seal packaging machine. To prevent variation in bag posturethat may be caused by the drop impact, the belt is preferably set in aposition so that it contacts the bags immediately after they areseparated from the supply roll of packaging material.

[0013] A vertical bag form-fill-seal packaging machine in accordancewith a fourth aspect of the present invention is the machine as definedin the third aspect, wherein the belt is inclined so that the bags movediagonally downward. In this case, with the belt inclined, the bagsseparated from the supply roll of the packing material surely contactthe belt. The incline of the belt is such that it allows the bags tomove diagonally downward, thereby reducing the impact that may be causedon the bags upon their contact with the belt, thus reducing changes inbag posture. Additionally, preventing the bags from being transferred ina stand-up posture, the bag-to-bag interval is more constant. Theincline of the belt further contributes to a reduction in the impactthat may be caused when the bags move from the belt to the transfer unitor conveyor in the downstream process.

[0014] A vertical bag form-fill-seal packaging machine in accordancewith a fifth aspect of the present invention is the machine as definedin the third or fourth aspect, wherein the first transfer unit includestwo belts holding each of the bags in a sandwiched manner. In this case,the bags are transferred while being held by the two belts in asandwiched manner. Thus, the bags are securely held, thereby reducingproblematic variations in the bag ejection pitch that may be caused bythe slippage of the bags and belt.

[0015] A vertical bag form-fill-seal packaging machine in accordancewith a sixth aspect of the present invention is the machine as definedin the fifth aspect, wherein the first transfer unit is such that a partof a transfer passage formed between the two belts is inclined so thatthe direction of the bag transfer changes as the bag moves therethrough.

[0016] A vertical bag form-fill-seal packaging machine in accordancewith a seventh aspect of the present invention is the machine as definedin the fifth or sixth aspect, further including a means for changing thedistance between the two belts, wherein the control unit controls themeans for changing the distance between the two belts according to thebags, so as to adjust the distance between the two belts. In this case,by taking advantage of the structure that holds each of the bags withthe two belts in a sandwiched manner, the volume of the gas to be filledinto the bags is optimized. In other words, by adjusting the distancebetween the two belts, the volume of the gas to be filled into theformed bags can be controlled, thus making the volume of the bags to beejected uniform. Generally with the vertical bag form-fill-sealpackaging machine, the gas to be filled is sprayed into the bags at thetime of bag forming. By spraying it with a little more than the requiredamount and making the volume of the bags uniform through the adjustmentof the belt-to-belt distance, the volume of the bags to be ejected willbe substantially uniform even if the pressure of the gas supply unit haschanged.

[0017] A vertical bag form-fill-seal packaging machine in accordancewith an eighth aspect of the present invention is the machine as definedeither in the fifth, sixth, or seventh aspects, wherein the sealing isheat-sealing and the machine further includes a cooling unit forspraying a cooling gas on the sealed part of each of the bags held in asandwiched manner by the two belts. In this case, by taking advantage ofthe structure that holds each of the bags in a sandwiched manner, a gasfor cooling is sprayed onto the bags thus held in a sandwiched manner,to ensure the bonding strength of the heat-sealed part. With aconventional machine, there is a high possibility that the posture ofthe bags to be ejected varies if a cooling gas is sprayed. However, withthe two belts sandwiching the bags in the machine of the presentinvention, the posture will rarely be affected even when cooled byspraying a gas. In addition, the cooling strengthens the sealing,thereby reducing the problem of bag breakage that may cause theproduction line to stop while the bags are still being transferred.

[0018] A vertical bag form-fill-seal packaging machine in accordancewith a ninth aspect of the present invention is the machine as definedin the first or second aspect, further including a second transfer unitfor receiving, transferring, and ejecting the bags transferred from thefirst unit, and a second drive unit for driving the second transferunit, wherein the control unit further controls the second drive unit inaddition to the first drive unit.

[0019] A vertical bag form-fill-seal packaging machine in accordancewith tenth aspect of the present invention is the machine as defined inthe ninth aspect, wherein the transfer unit is a belt with a guide barapproximately orthogonal to the direction of transfer. In this case, thetransfer unit, which is a belt, has a guide bar that prevents the bagsfrom shifting on the bag.

[0020] A vertical bag form-fill-seal packaging machine in accordancewith an eleventh aspect of the present invention is the machine asdefined in any of the previous aspects, further including a memorystorage unit for storing control settings for each set of products to bepackaged, wherein the control unit maintains control according to thesettings stored in the memory storage unit.

[0021] A vertical bag form-fill-seal packaging machine in accordancewith a twelfth aspect of the present invention is the machine as definedin the eleventh aspect, wherein at least one of the control settingitems to be stored in the memory storage unit is the speed of the driveunit. In this case, by setting the drive unit speed according to thebags, it becomes possible to adjust the bag-to-bag pitch to be ejectedand the bag ejection time interval to reflect the operating conditionsof the equipment in the downstream process.

[0022] A vertical bag form-fill-seal packaging machine in accordancewith a thirteenth aspect of the present invention is the machine asdefined in the twelfth aspect, wherein the control unit provides data atleast on the bag ejection time interval to the external equipment in thedownstream process. In this case, because the data on the time intervalbetween each bag's ejection are provided to the external equipment inthe downstream process, an operation synchronizing with the ejectiontime intervals of the bags sent from the vertical bag form-fill-sealpackaging machine becomes possible.

[0023] These and other objects, features, aspects and advantages of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which, taken in conjunction with theannexed drawings, discloses a preferred embodiment of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Referring now to the attached drawings which form a part of thisoriginal disclosure:

[0025]FIG. 1 is a schematic diagrammatical view of a conventionalvertical bag form-fill-seal packaging machine with devices in theupstream and downstream processes;

[0026]FIG. 2 is a schematic diagrammatical view illustrating an exampleof a production line for a downstream process for a bag ejected from aconventional vertical bag form-fill-seal packaging machine;

[0027]FIG. 3 is a schematic structural diagrammatical view of aconventional vertical bag form-fill-seal packaging machine;

[0028]FIG. 4 is an elevational view of a vertical bag form-fill-sealpackaging machine in accordance with a first embodiment of the presentinvention;

[0029]FIG. 5 is a control block diagrammatical view of the vertical bagform-fill-seal packaging machine of FIG. 4;

[0030]FIG. 6 is an elevational view of the adjacent area of the forcedejector of FIG. 4;

[0031]FIG. 7 is an elevational view of the adjacent area of the forcedejector in accordance with a second embodiment of the present invention;

[0032]FIG. 8 is a rear elevational view of the adjacent area of theforced ejector of FIG.7;

[0033]FIG. 9 is an elevational view of the adjacent area of the forcedejector in a variation of the second embodiment; and

[0034]FIG. 10 is an elevational view illustrating how the belt-to-beltdistance of the forced ejector is changed in another variation of thesecond embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First EmbodimentCompared to the Prior Art

[0035] A conventional measuring and bag forming/packaging line isillustrated in FIG. 1, together with an example of devices in theupstream and downstream processes. In this case, a product for example,potato chips, is transferred by a supply conveyor 101 to a positionabove the measuring unit 110. The product, once in the measuring unit110, is measured into a predetermined weight (or quantity) andcontinuously discharged downward.

[0036] The product discharged from the measuring unit 110 moves into avertical bag form-fill-seal packaging machine 120 located under themeasuring unit 110. The vertical bag form-fill-seal packaging machine120 is a device for forming bags, and filling and packing a product inthe bags simultaneously. The bags containing the product as a result ofthe packaging slides down the stationary chute 129 provided with thevertical bag form-fill-seal packaging machine 120, and are loaded ontothe transfer conveyor 130. The transfer conveyor 130 transfers the bagscontinuously discharged there to a weight checker 140 in the downstreamprocess.

[0037] If bags need to be continuously packed in carton boxes, the bagsare transferred from the transfer conveyor 130 to the weight checker 140and a sealing checker 150 as shown in FIG. 2. The bags subjected to theweight and sealing checks here go through a directing unit 160 and aposture adjustment unit 170 so that they are sent to a boxing unit 180in a file or files.

[0038] The boxing unit 180 is provided with a handling mechanism 181holding the bags through suction, to pack the bags B into a carton box.The carton box in which the bags B are packed is transferred via acarton box transferring unit 190 to a box-sealing unit and a labelingunit (not shown).

[0039]FIG. 3 shows the major structure of a conventional vertical bagform-fill-seal packaging machine 120, the so-called vertical pillowpackaging machine. In the vertical bag form-fill-seal packaging machine120, sheet-like film Fm drawn from a roll of film 128 (see FIG. 1) isformed into a tubular shape through a former 121 and a tube 122 and feddownward by a pull-down belt mechanism 125. The overlapped vertical endsof the tubular film Fmc is heat-sealed by a vertical sealing mechanism123. When the measured product fills the tubular film Fmc through thetube 122, the transverse sealing mechanism 124 provided under the tube122 performs transverse sealing in the area that will become the top ofthe bag preceding and the bottom of the following bag. Concurrently withthe transverse sealing, the center of the transversely sealed part iscut by a cutter built in the transverse sealing mechanism 124. The bagsthus cut slide down on the stationary chute 129 provided under thetransverse sealing mechanism 124, and then transferred on a transferconveyor 130 to the devices in the downstream processes.

[0040] Overall Structure

[0041] A vertical bag form-fill-seal packaging machine in accordancewith the first embodiment of the present invention is described below.

[0042]FIG. 4 shows a vertical bag form-fill-seal packaging machine 1,including a forced ejector 6 in accordance with a first embodiment ofthe present invention. The vertical bag form-fill-seal packaging machine1 is a machine for packing a product such as food for example, potatochips into bags, mainly including a bag-forming/packaging section 5, afilm supply unit 4, and a forced ejector 6. The bag forming/packagingsection 5 is a main region for packing the product into bags. The filmsupply unit 4 supplies the bag-forming/packaging section 5 with the filmthat ultimately becomes bags. The forced ejector 6 forcibly ejectsdownward the bags formed by the bag-forming/packaging section 5. Anoperation switch 7 (see FIG. 5) is provided at the front of the verticalbag form-fill-seal packaging machine 1. A liquid-crystal display 8 forshowing the status of the operation is provided where the operatormanipulating the operation switch can visually check operations. Thecontrol unit 20 shown in FIG. 5 controls the operation of each of thedrive units for the vertical bag form-fill-seal packaging machine 1 anddisplays various data on the liquid-crystal display 8 based on the inputfrom the operation switch 7.

[0043] A Structure of the Film Supply Unit

[0044] Referring to FIG. 4, the film supply unit 4 supplies sheet-likefilm to a forming mechanism 13 in the bag-forming/packaging section 5that is to be described later. A roll of film is set on the film supplyunit 4 so that the film Fm is unreeled from the roll.

[0045] A Structure of the Bag-Forming/Packaging Section

[0046] As shown in FIG. 4, the bag-forming/packaging section 5 includesthe forming mechanism 13, a pull-down belt mechanism 14, a verticalsealing mechanism 15, and a transverse sealing mechanism 17. The formingmechanism forms the film Fm that is fed in as a sheet into a tubularshape. The pull-down belt mechanism 14 transfers the tubular-shaped film(hereinafter called “tubular film Fmc”) downward. The vertical sealingmechanism 15 vertically seals the overlapped part of the tubular filmFmc. The transverse sealing mechanism 17 transversely seals the tubularfilm Fmc to close the top and bottom of each of the bags.

[0047] As shown in FIG. 4, the forming mechanism 13 has a tube 31 and aformer 32. The tube 31 is a cylindrical member with its top and bottomends open. The tube 31 is made integral with the former 32 through abracket. Measured items such as potato chips are put into the open topend of the tube 31 from the measuring unit 11. The former 32 is providedin such a manner that it surrounds the tube 31. The shape of the former32 is such that allows the sheet-like film Fm fed from the film supplyunit 4 to be formed into a tubular shape when it passes between theformer 32 and the tube 31. The pull-down belt mechanism 14 is amechanism for sucking the film Fm wound on the tube 31 to pick it up andtransfer it downward. The pull-down belt mechanism mainly includes adriver roller 41 and a driven roller 42, as well as a suction belt 43.The vertical sealing mechanism 15 vertically seals the overlapped partof the film Fm wound on the tube 31 by heating it while pressing itagainst the tube 31 at a predetermined pressure. The vertical sealingmechanism 15 has a heater and a heater belt that contacts the overlappedpart of the film Fm when heated by the heater.

[0048] The transverse sealing mechanism 17 is provided beneath theforming mechanism 13, the pull-down belt mechanism 14, and the verticalsealing mechanism 15. As shown in FIG. 6, the transverse sealingmechanism 17 has a pair of symmetrical sealing jaws. The two sealingjaws 17 a, each of which turns in the shape of the letter “D”, leavingtracks T that are symmetrical to each other. The sealing jaws 17 a matewith each other when the tubular film Fmc is ready to be transverselysealed. The transverse sealing mechanism 17 has a cutter not shown inthe drawing. The cutter separates the bag from the tubular film Fmc thatfollows the bag at the center of the part sealed by the sealing jaws 17a. The transverse sealing mechanism 17 crimps the part to betransversely sealed by sandwiching the tubular film Fmc between thesealing jaws 17 a, a process that requires heat in addition to pressure.Therefore, in order to heat the mating surfaces of the sealing jaws 17 athat contact the tubular film Fmc, a heater is provided in the each ofthe sealing jaws 17 a, and a thermocouple is attached thereto as well.

[0049] A Structure of the Forced Ejector

[0050] The forced ejector 6 mainly includes an endless belt 61, a driverroller 62, a driven roller 63, and an AC servo motor 64. The servo motor64 turns the driver roller 62 and provides super-fine turning control.The servo motor 64 is controlled by the control unit 20 as shown in FIG.5. As shown in FIG. 6, the belt 61 is inclined so that the bag B movesdiagonally downward. Still referring to FIG. 6, the forced ejector 6 ispositioned at a height that enables the bottom of the bag B to contactwith the upper side of the belt 61 when the bag B is separated by thecutter provided in the sealing jaws 17 a. If the forced ejector 6 is ata position higher than this, the belt 61 will thrust the bag B upwardbefore the transverse sealing is completed, resulting in a poortransverse sealing. Conversely, if the forced ejector 6 is located toolow, the falling distance to the point where the separated bag Bcontacts the belt 61 becomes too long, thus causing the bag B to bounceon the belt 61 and deteriorating the stability of the posture of the bagB.

[0051] A Structure of the Control Unit

[0052] As shown in FIG. 5, the control unit 20 is connected with thefilm supply unit 4, bag-forming packaging sections 5, and forced ejector6 of the vertical bag form-fill-seal packaging machine 1 to control theoperation of each of the drive units. First, the control unit 20controls the rotating speed of the sealing jaws 17 a of the transversesealing mechanism 17 as well as the traveling speed of belt 61 of theforced ejector 6 according to the downward feeding speed of the tubularfilm Fmc on the pull-down belt mechanism 14. In controlling the forcedejector 6, the rotating speed of the servo motor 64 is controlledaccording to the feeding speed of the tubular film Fmc, i.e. thebag-forming/packaging section 5 bag-forming capacity, to change theejection speed of the bag B (the traveling speed of the belt 61) at theforced ejector 6. In this production line, an AC servo motor 131 isemployed as a driving power source for the transfer conveyor 130. Theservo motor 131 is controlled according to the data on the ejectingspeed of the forced ejector 6 and the bag ejection time interval thatare output from the control unit 20. The controlling of the servo motor64 for the forced ejector 6 and the servo motor 131 for driving thetransfer conveyor 130 may be carried out by changing the rotating speedto adjust the ejection interval between the bags B, or by performing anintermittent driving to repeat ON/OFF switching of operations to adjustthe bags B′ ejection interval.

[0053] Further, the control unit 20 has an external output terminal 21,which can send the data on the bags B ejecting speed and bag ejectiontime interval to the transfer conveyor 130 and other devices in thedownstream process (the weight checker 140, the sealing checker 150, theboxing unit 180, and the like shown in FIG. 2). In the control unit 20,a memory storage unit such as a hard disc is also provided. Data on theshape, dimensions, material, volume, and the like for each set of thebags are stored in the memory storage unit, and the control patterns foreach of the drive units, including the appropriate controlling patternfor the transfer speed of the forced ejector 6, are preset.

[0054] An Operation of the Vertical Bag Form-Fill-Seal Packaging Machine

[0055] An operation of the vertical bag form-fill-seal packaging machine1 is described below.

[0056] Referring to FIG. 4, the sheet-like film Fm fed from the filmsupply unit 4 to the forming mechanism 13 moves through the former 32and is wound on the tube 31. The sheet-like film Fm is shaped in atubular form and transferred, in this condition, downward by beingcarried on the pull-down belt mechanism 14. When wound on the tube 31,the film Fm has both ends overlapped on its circumference. Theoverlapped part is to be vertically sealed by the vertical sealingmechanism 15. The tubular film Fmc, now in a cylindrical form as aresult of the vertical sealing, moves out of the tube 31 and down to thetransverse sealing mechanism 17. At this point, the position of thetubular film Fmc is in the area indicated by the double-dot dash line inFIG. 4. Now, concurrently with the travel of the tubular film Fmc, amass of items, for example, potato chips, falls from the measuring unit110 via the tube 31. At the transverse sealing mechanism 17, the bottomand the top of the bag are transversely sealed, in sequence, with thepotato chips present in the tubular film Fmc. In the process oftransverse sealing by the transverse sealing mechanism 17, the cuttingprocess by the cutter provided in the sealing jaws 17 a is carried outconcurrently as shown in FIG. 6. The cutter cuts the approximate centerof the transversely sealed part. Thus, as seen in FIG. 4, the bag B isseparated from the tubular film Fmc that follows, and contacts the upperpart of the belt 61 of the forced ejector 6 and is forcibly carrieddiagonally downward according to the turn of the belt 61.

[0057] In this process, if the bag B contacts the belt 61 at a speedlower than the traveling speed of the belt 61, the bags B may be bridgedand tip forward. If the traveling speed of the belt 61 is substantiallyhigher than the falling speed of the bag B, the belt surface may not beable to catch the bag B. Therefore, the traveling speed of the belt 61is set equivalent to or a little higher than the falling speed of thebag B. The maximum value of this speed setting varies with the materialsof the belt 61, the film Fm, and the weight of the filled bag B.Therefore, the control unit 20 considers these conditions in controllingthe rotating speed of the servo motor 64 to adjust the traveling speedof the belt 61.

[0058] In setting a specific traveling speed for the belt 61, thedistance between the transverse sealing mechanism 17 and the belt 61,the falling speed of the bag B upon separation, gravitationalacceleration, and the like are used as the bases for calculation.

[0059] The vertical bag form-fill-seal packaging machine, in accordancewith the first embodiment of the present invention, has the followingfeatures:

[0060] The vertical bag form-fill-seal packaging machine 1 is providedwith the forced ejector 6 instead of a conventional stationary chute 129as seen in FIG. 3. Thus, variation of the ejection pitch and thepostures of the bag B ejected onto the transfer conveyor 130 isprevented. With a conventional stationary chute, on which frictionalresistance is applied when the bag B slides down or the impact is causedwhen falling, there is a high possibility that the ejection pitch andthe posture of the bag B may become uneven. By using the forced ejector6, the belt 61 is allowed to contact with the bag B so that the bag B,together with the belt 61, can be forcibly moved through the turn of thedriver roller 62, thereby preventing the variation of the pitch and theposture of the bag as shown in FIG. 4.

[0061] In the vertical bag form-fill-seal packaging machine 1, the belt61 is provided in a slanted manner instead of vertically, to ensure thatthe bag B separated from the tubular film Fmc contacts the belt 61.Also, the incline of the belt 61 is such that the bag B moves diagonallydownward, thus reducing the impact that may be caused when the bag Bcontacts with the belt 61, as well as minimizing the change in theposture of the bag B. This also reduces the problem that the bag B maybe transferred in a stand-up posture. As shown in FIG. 6, the incline ofthe belt 61 also contributes to a reduction in the impact that may becaused when the bag B moves from the belt 61 to the transfer conveyor130.

[0062] Referring now to FIG. 5 in the vertical bag form-fill-sealpackaging machine 1, the control unit 20 takes control of linking thebag-forming capacity of the bag-forming/packaging section 5 with theejection (traveling) speed of the bag B by the forced ejector 6, therebyenabling the pitch and the ejection time interval of the bag B ejectedby the forced ejector 6 onto the transfer conveyor 130 in the downstreamprocess to be set to predetermined values. Even with the bag-formingcapacity varied between low speed (low throughput) and high speed (highthroughput), the pitch between the bags B to be ejected and the ejectiontime interval between the bags B can be adjusted to suit the externaldevices of the downstream processes such as the weight checker 140, thesealing checker 150, and the boxing unit 180 by controlling the servomotor 64 for the forced ejector 6 to change the ejecting speed of thebag B.

[0063] In the vertical bag form-fill-seal packaging machine 1 inaccordance with the first embodiment of the present invention, the ACservo motor 131 is employed as a driving power source for the transferconveyor 130, to control the transferring speed of the transfer conveyor130 according to the ejecting speed (traveling speed) and the ejectiontime interval for the bag B at the forced ejector 6. Therefore, even inhigh-speed forming of the bag B with an improved capacity of thevertical bag form-fill-seal packaging machine 1, the transfer of the bagB from the bag-forming/packaging section 5 to the forced ejector 6 andfrom the forced ejector 6 to the transfer conveyor 130 become smooth bysynchronizing the ejecting speed of the forced ejector 6 and thetransfer conveyor 130 to aforesaid speeds, thus preventing thedeterioration of the posture and the pitch of the bag B.

[0064] The control unit 20 of the vertical bag form-fill-seal packagingmachine 1 controls the transfer speed of the transfer conveyor 130according to the ejecting speed of the forced ejector 6. The controlunit 20 also provides data such as the ejecting speed, the ejection timeinterval, ejection pitch (interval between the bag tops or the bagsthemselves, bag length, and the like) at the forced ejector 6 to theexternal equipment in the downstream process via the external outputterminal 121. This enables process control at the external equipment (ata device in the downstream process) such as the weight checker 140, thesealing checker 150, and boxing unit 180 that takes advantage ofaforesaid data.

[0065] For example, the external equipment that has received the data onthe ejection time interval and the ejection pitch (bag-to-bag distance)sets the processing speed and the transferring speed according to theejection time interval; if the ejection pitch is too small, thetransferring speed is increased so that the bag-to-bag interval isincreased. The ejecting speed can be obtained from the followingformula:

(Bag length+bag-to-bag distance)/(ejection time interval).

[0066] The bag-to-bag distance can be obtained from the followingformula:

(Ejecting speed)×(ejection time interval)−(bag length).

[0067] The external equipment can be controlled properly for processingwith the data on (ejection time interval); (bag length); and (ejectingspeed) or (bag-to-bag distance). Some variations of the first embodimentare described below as examples.

[0068] (1) In the aforesaid embodiment, the forced ejector 6 includingthe belt 61, the driver roller 62, driven roller 63, and the servo motor64 is incorporated in the vertical bag form-fill-seal packaging machine1. The ejector may be provided as a device independent from the verticalbag form-fill-seal packaging machine. In such a case, the forced ejector6 including the belt 61, the driver roller 62, driven roller 63, and theservo motor 64 should be provided beneath the vertical bagform-fill-seal packaging machine. In this way, the forced ejector can beretrofitted to a conventional vertical bag form-fill-seal packagingmachine after the removal of the stationary chute.

[0069] (2) In the first embodiment described so far, the forced ejector6 includes the belt 61 that contacts the bag B and the driver roller 62or the like that lets the belt 61 travel. It is also possible to use amechanism for forcibly feeding the bag B without touching the bag B tomake the forced ejector 6. For example, a vacuuming mechanism forsucking to draw the bag B separated by the transverse sealing mechanism17 may be provided below the transverse sealing mechanism 17. It is alsopossible to provide a mechanism for generating an air flow around thebag B to be separated.

[0070] (3) In the aforesaid first embodiment, the transferring speed ofthe transfer conveyor 130 is linked with the vertical bag form-fill-sealpackaging machine 1 by utilizing the external output terminal 21 of thecontrol unit 20. The transfer conveyor 130 may also be incorporated intothe vertical bag form-fill-seal packaging machine 1 for the purpose ofcontrolling the transferring speed and ejection time interval in thesame manner of handling as do the bag-forming/packaging section 5 andthe forced ejector 6.

[0071] (4) On the belt 61 and the belt for the transfer conveyor 130 ofthe aforesaid first embodiment, a guide bar may be provided so that onlyone of the bags B fits in each space created by the guide bar. Byproviding such a guide bar at an appropriate interval on the belt, theuniformity of the ejection interval between the bags B increases. It ispreferable to provide the guide bar so that it is orthogonal to thedirection of the belt transfer, to prevent the positional shifting ofthe bag B on the belt.

[0072] (5) As the belt 61 and the belt for the transfer conveyor 130 ofthe aforesaid first embodiment, a plurality of round belts or a vacuumsuction belt also may be employed.

Second Embodiment

[0073] Referring mainly to FIG. 7, vertical bag form-fill-seal packagingmachine, in accordance with a second embodiment of the presentinvention, is a machine for packing a product such as food (potato chipsin this case) into bags. The machine mainly includes abag-forming/packaging section, film supply unit, a forced ejector 206,and a cooling section 9. The structure of the film supply unit and thebag-forming/packaging section are the same as those in the firstembodiment. The bag-forming/packaging section is a main region forpacking the product into bags, a film supply unit 4 supplies thebag-forming/packaging section with the film that ultimately becomesbags. The forced ejector 206 forcibly ejects downward the bags formed bythe bag-forming/packaging section. The cooling section 9 forcibly coolsthe bags formed by the bag-forming/packaging section. An operationswitch, a liquid-crystal display, and a control unit are also providedin the same manner as in the first embodiment of the present invention.

[0074] Structure of the Forced Ejector

[0075] As shown in FIG. 7, the forced ejector 206 mainly includesendless belts 261 a & 261 b, driver rollers 262 a & 262 b, drivenrollers 263 a & 263 b, and an AC servo motor. The servo motor forturning the driver rollers 262 a & 262 b is a motor capable of providingextremely fine turning control, and is controlled by the control unit(not shown). The belt 261 a is placed on one driver roller 262 a andthree driven rollers 263 a so that it travels in a manner to move thebag B downward according to the rotation of the driver roller 262 a. Thebelt 261 b is placed on one driver roller 262 b and three driven rollers263 b so that it travels in a manner to move the bag B downwardaccording to the rotation of the driver roller 262 b.

[0076] As shown in FIG. 8, the belt 261 b is provided with openings 269at a uniform interval to prevent its interference with the sealing jaws17 a. Also, the driver roller 262 b and the driven rollers 263 b areprovided so that they are placed underneath the both ends of the belts261 b to prevent their interference with the sealing jaws 17 a as seenin FIG. 7. The belt 261 a is similarly constructed. As seen in FIG. 7,the belt 261 b extends downward farther than the belt 261 a, to assistin the loading of the bag B onto the transfer conveyor 130.

[0077] A part of the transfer passage formed between the belts 261 a &261 b may be inclined between the vertical area and the horizontal areaso that the direction for transferring the bag B changes from verticalto horizontal as the bag moves through the passage. The rotation of thedriver rollers 262 a & 262 b is controlled so that the belts 261 a & 261b travel at a constant speed.

[0078] Structure of the Cooling Section

[0079] The cooling section 9, which includes two air sprayers 9 a, isprovided inside the loops of the endless belts 261 a & 261 b to sprayair through the opening in the belts 261 a & 261 b to the bag B that isfed downward by the belts 261 a & 261 b. The ON/OFF switching and thespraying volume of the air sprayers 9 a are maintained by the controlunit.

[0080] Operation of the Vertical Bag Form-Fill-Seal Packaging Machine

[0081] An operation of the vertical bag form-fill-seal packaging machinein accordance with the second embodiment is described below.

[0082] As with the first embodiment, the sheet-like film fed from thefilm supply unit to the forming mechanism moves through the former andis wound on tube. The sheet-like film is shaped in a tubular form andtransferred, in this condition, downward by being carried on thepull-down belt mechanism. When wound on the tube, the film has both endsoverlapped on its circumference, and the overlapped part is to bevertically sealed by the vertical sealing mechanism.

[0083] The tubular film Fmc, now in a cylindrical form as a result ofthe vertical sealing, moves out of the tube and down to the transversesealing mechanism. At this point, concurrently with the travel of thetubular film Fmc, a mass of items, for example potato chips falls fromthe measuring unit via the tube. Now, through the transverse sealingmechanism, the bottom and the top of the bag are transversely sealed insequence, with the items, for example potato chips present in thetubular film Fmc.

[0084] As seen in FIG. 7, in the process of transverse sealing by thetransverse sealing mechanism 17, the cutting process by the cutterprovided in the sealing jaws 17 a is carried out concurrently. Thecutter cuts the approximate center of the transversely sealed part.Also, prior to the process of transverse sealing, the bag B (yet to betransversely sealed) is held by the belts 261 a & 261 b that come intocontact with the bag on both sides, and forcibly fed downward. Thefeeding speed is controlled by the control unit to be synchronous withthe feeding speed on the pull-down belt mechanism and the travelingspeed of the sealing jaws 17 a.

[0085] The bag B that has moved out of the transverse sealing mechanism17 is subjected to the air sprayed from the cooling section 9 while itis held by the belts 261 a & 261 b of the forced ejector 206 in asandwiched manner and being transferred downward. This cools theheat-sealed part, thus increasing its bonding strength before the bag Bis loaded on the transfer conveyor 130.

[0086] As shown in FIG. 7, the bag B that has moved out of the coolingsection 9 leaves the belts 261 a & 261 b and is loaded on the transferconveyor 130 and carried thereon to devices such as the weight checkerin a downstream process. The vertical bag form-fill-seal packagingmachine in accordance with the second embodiment, of the presentinvention has the following features:

[0087] By turning the belts 261 a & 261 b through the driver rollers 262a & 262 b to move the bag B downward while holding the bag B with thetwo belts 261 a & 261 b of the forced ejector 206 in a sandwichedmanner, the bag B is forcibly moved to the transfer conveyor 130 in thesecond embodiment. Thus, by holding the bag B with the two belts 261 a &261 b in a sandwiched manner, problems such as slippage of the belts 261a & 261 b resulting in a variation of the pitch of the bags B to beejected can be reduced.

[0088] Taking advantage of the structure for holding bag B with the twobelts 261 a & 261 b in a sandwiched manner, cooling air is sprayed uponbag B thus held to ensure the bonding strength of the heat-sealed partof the formed bag B.

[0089] In a conventional machine, the sealed part (particularly thetransversely sealed part) of the bag B may be sent to the device in adownstream process without sufficiently being cooled down, or air isblown on the bag B on a transfer conveyor with a cooling fan. However,in blowing wind upon the bag B on the transfer conveyor, there is a needto restrict the air volume so that the position of the bag B will not beshifted, which makes it difficult to achieve a sufficient cooling effectin a high-speed operation.

[0090] To counter this problem, the second embodiment achieves acondition in which the posture hardly will be affected, even withair-spray cooling, through the method of holding the bag B with the twobelts 261 a & 261 b in a sandwiched manner. It employs a structure inwhich air is sprayed with the air sprayer 9 a to the bag held by thebelts 261 a & 261 b in a sandwiched manner. This allows effectivecooling of the heat-sealed part of the formed bag B, thus reducing bagbreakage even with high-speed ejection of the bag B. Some variations ofthe second embodiment are described below as examples.

[0091] (1) In the aforesaid second embodiment, the bag B that has leftthe belts 261 a & 261 b moves almost vertically until it hits againstthe transfer conveyor 130 as shown in FIG. 7. In a high-speed operation,the impact caused when the bag B comes up against the transfer conveyor130 may be great. To reduce the impact, a forced ejector 306 as shown inFIG. 9 may be employed instead of the forced ejector 206.

[0092] The forced ejector 306 shown in FIG. 9 includes endless belts 361a & 361 b, driver rollers 362 a & 362 b, driven rollers 363 a & 363 b, adirection-changing driven roller 364, and an AC servo motor. The servomotor for turning the driver rollers 362 a & 362 b provides extremelyfine turning control, and is controlled by a control unit. The belt 361a is placed on one driver roller 362 a and three driven rollers 363 a sothat it travels in a manner to move the bag B downward according to therotation of the driver roller 362 a. The belt 361 b is placed on onedriver roller 362 b, three driven rollers 363 b, and thedirection-changing driven roller 364 so that it travels in a manner tomove the bag B downward according to the rotation of the driver roller362 b.

[0093] The belts 361 a & 361 b are provided with openings at a uniforminterval to prevent its interference with the sealing jaws 17 a. Thedriver rollers 362 a & 362 b, the driven rollers 363 a & 363 b, and thedirection-changing driven roller 364 are provided so that they comeunder the both ends of the belts 361 a & 361 b to prevent theirinterference with the sealing jaws 17 a. The rollers 362 a, 362 b, 363a, 363 b, & 364 are provided in the positions shown in FIG. 9, so thatthe bag B, after leaving the cooling section 9, moves in a differentdirection, changing from vertical to horizontal, toward the transferconveyor 130. The rotation of the driver rollers 362 a & 362 b iscontrolled so that the belts 361 a & 361 b travel at a constant speed.Thus, the structure of the forced ejector 306 in the second embodimentis made to allow, in its lower portion, the bag B to move toward thehorizontal direction; i.e. the surface on which the bag B below the belt361 b comes into contact is inclined so that the bag is ejectedhorizontally onto the transfer conveyor 130. This significantly reducesthe impact that may be caused when the bag B is loaded onto the transferconveyor 130

[0094] (2) Referring to FIG. 7, the forced ejector 206 in the secondembodiment may further be provided with a function to optimize thevolume of the gas to be filled in the bag B. In such a case, thedistance between the belts 261 a & 261 b of the forced ejector 206 ismade variable by a means for changing the belt-to-belt distance. Thedistance between the belts 261 a & 261 b is also controlled by thecontrol unit 20 according to the type of the bag B and the volume of thegas required to fill the bag.

[0095] A possible example of the means for changing the belt-to-beltdistance is a mechanism that moves a first unit having the belt 261 a,the driver roller 262 a, and the driven roller 263 a, and a second unithaving the belt 261 b, the driver roller 262 b, and the driven roller263 b to the right or left by using motorized ball screws and a servomotor. As shown in FIG. 10, this makes it possible to shift each elementof the forced ejector 206 from the position shown with the solid line tothe position shown with the broken line, and to change the distancebetween the belts 261 a & 261 b into any value with the control unit.Then, by adjusting the distance between the belts 261 a & 261 b whilesetting the volume of the gas to be filled which is sprayed from abovethe tubular film Fmc somewhat higher, the volume of the gas to be filledin the bag B, or the volume of the bag B, is made uniform.

[0096] In a conventional machine, the volume of the gas to be filled isadjusted by varying the period of the spraying time, for example.However, if the gas supply sources are centralized in a large-scaleplant, the supply pressure of the gas supply source often varies, thusmaking it difficult to prevent variation in the volume of gas to befilled. A variation in the volume of gas to be filled results in avariation in the volume of the bag B, leading to a problem at the boxingunit in a downstream process. The boxing unit packs a specified numberof the bags B into carton boxes by the use of a handling mechanism thatutilizes suction or the like. If the volume of the bag B is not constantas described above, the following problems may occur: mishandling, bagbreakage, a gap in the carton box after the specified number of the bagsB are placed inside. Thus problems during transportation, and a failureto pack the specified number of the bags B in the carton box may result.

[0097] To counter the above, this variation of the second embodiment, bytaking advantage of structures for holding the bag B with the two belts261 a & 261 b in a sandwiched manner and by adjusting the distancebetween the two belts 261 a & 261 b, enables the controlling of thevolume of the gas to be filled in the formed bag B, thus achievinguniformity of the volume of the bag B. This allows the bag B, almostuniform in volume, to be supplied to the devices in a downstreamprocess, which should reduce the incidence of problems in the devicesduring the downstream process.

[0098] The terms of degree such as “substantially”, “about” and“approximately” as used herein mean a reasonable amount of deviation ofthe modified term such that the end result is not significantly changed.These terms should be construed as including a deviation of at least ±5%of the modified term if this deviation would not negate the meaning ofthe word it modifies.

[0099] While only selected embodiments have been chosen to illustratethe present invention, it will be apparent to those skilled in the artfrom this disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing description of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A vertical bag form-fill-seal packaging machinefor forming bags by sealing a continuous tubular packaging material inwhich a product to be packaged is filled, and for separating andejecting each of the bags, the machine comprising: a first transfer unitfor transferring the separated bags to another transfer unit or transfermachine provided in a downstream process, a first drive unit for drivingthe first transfer unit, and a control unit for controlling the firstcontrol unit, said control unit controlling the bag ejection interval orthe posture of the bags to be ejected after being transferred by thefirst transfer unit.
 2. The machine as defined in claim 1, wherein thecontrol unit provides control so that the bag ejection interval islarger than the bag separation interval.
 3. The machine as defined inclaim 1, wherein the first transfer unit is a belt.
 4. The machine asdefined in claim 2, wherein the first transfer unit is a belt.
 5. Themachine as defined in claim 3, wherein the belt is inclined so that thebags move diagonally downward.
 6. The machine as defined in claim 4,wherein the belt is inclined so that the bags move diagonally downward.7. The machine as defined in claim 3, wherein the first transfer unitcomprises two belts holding each of the bags in a sandwiched manner. 8.The machine as defined in claim 7, wherein the first transfer unit issuch that a part of a transfer passage formed between the two belts isinclined so that the direction of the bag transfer changes as the bagmoves therethrough.
 9. The machine as defined in claim 7, furthercomprising a means for changing the distance between the two belts,wherein the control unit controls the means for changing the distancebetween the two belts according to the bags, so as to adjust thedistance between the two belts.
 10. The machine as defined in claim 8,further comprising a means for changing the distance between the twobelts, wherein the control unit controls the means for changing thedistance between the two belts according to the bags, so as to adjustthe distance between the two belts.
 11. The machine as defined in claim7, wherein the sealing is heat-sealing and the machine further comprisesa cooling unit for spraying a cooling gas on the sealed part of each ofthe bags held in a sandwiched manner by the two belts.
 12. The machineas defined in claim 1, further comprising: a second transfer unit forreceiving, transferring, and ejecting the bags transferred from thefirst transfer unit, and a second drive unit for driving the secondtransfer unit, wherein the control unit further controls the seconddrive unit.
 13. The machine as defined in claim 12, wherein the transferunit is a belt with a guide bar approximately orthogonal to thedirection of transfer.
 14. The machine as defined in claim 1, furthercomprising a memory storage unit for storing control settings for eachset of products to be packaged, wherein the control unit performscontrol according to the settings stored in the memory storage unit. 15.The machine as defined in claim 14, wherein at least one of the controlsetting items to be stored in the memory storage unit is the speed ofthe drive unit.
 16. The machine as defined in claim 15, wherein thecontrol unit provides data at least on the bag ejection time interval tothe external equipment in the downstream process.
 17. The machine asdefined in claim 7, further comprising a memory storage unit for storingcontrol settings for each set of products to be packaged, wherein thecontrol unit performs control according to the settings stored in thememory storage unit.
 18. The machine as defined in claim 17, wherein atleast one of the control setting items to be stored in the memorystorage unit is the speed of the drive unit.
 19. The machine as definedin claim 18, wherein the control unit provides data at least on the bagejection time interval to the external equipment in the downstreamprocess.